1. Field of the Invention
This invention relates generally to transmission of messages through the Iridium Short Burst Data Service. More specifically, this invention relates to transmission of ground to-air and air-to ground messages, conforming to Airlines Electronics Engineering Committee Specification 618, through the Iridium Short Burst Data Service.
2. Description of Related Art
Aircraft Communication Addressing and Reporting System (ACARS) is a well-known data protocol defined by Airlines Electronic Engineering Committee (AEEC) Specification 618. ACARS provides connectivity for character-based data between an aircraft and one or more ground-based service providers.
VHF communication provides only line-of-sight communication coverage while satellite communication provides oceanic and polar communication coverage. However, satellite communication has been expensive for use with ACARS. The Iridium Short Burst Data Service is a lower cost alternative to conventional satellite communication. The Iridium Short Burst Data Service is designed, such that small data messages or frequently transmitted data messages may be sent more economically compared with transmitting the messages via circuit switched data services.
Equipment on board commercial aircraft adhere to AEEC specifications. Systems have been developed which provide ACARS-like messages sent through the Iridium satellite network. However, these systems do not support ACARS air/ground protocol and therefore, the ACARS-like messages cannot be passed to existing avionic equipment aboard an aircraft.
The ACARS air/ground protocol provides for transmission of messages in pieces called blocks. According to the protocol, receipt of each block is acknowledged. Elements of the message blocks may convey information to the avionic equipment, such as, for example, peripheral addressing information or other information. The systems, which provide ACARS-like messages, do not provide the information conveyed by the elements of the message blocks to the avionic equipment. Commercial airlines, using the systems which provide ACARS-like messages, are incapable of conveying the information from the elements of the message blocks to the avionics equipment without either revamping or replacing the existing avionics equipment. However, such revamping or replacing of the existing avionics equipment may cause the equipment to no longer comply with AEEC specification 618.